Method of manufacturing glass.



To all whom it may concern:

UNITED STATES PATENT OFFICE.

JAMES RAMSEY SPEER, or PITTSBURGH. AND GEORGE H. HARVEY, on GrLENFIELD,PENNSYLVANIA, ASSIGNORS To BROWNSVILLE GLASS ooMPANY, OF PITTSBURG,PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

Be it known that we, JAMES RAMS Y SPEER, residing at Pittsburg, andGEORGE H.

- HARVEY, residing at Glenfield, .in the county of Allegheny and Stateof Pennsylvania, citizens of the United Statesfhave invented ordiscovered new and useful Improvements in- Methods of ManufacturingGlass, of which the following is a specification;

. Our-invention relates to the method of drawing cylinders from moltenor plastic glass, then dividingthe same into segments and also, ifdesired, into sections transversely of the cylinders, and, finally, ifpreferred, causin the segmental lengths or sections to have p anesurfaces.

Our method contemplates the drawing of glass cylinders of much greaterdiameter.

than. has hitherto been found practicable for the manufacture of windowor other similar drawn glass; b ut we .do not desire to be restricted toany minimumdiameter of the cylinders when the steps succeeding thedrawing operation are substantially those which We practice or are fairequivalents of the same. l

In the manufacture of common window- 'glass by machinery it is thepractice at present to draw glass cylindersof from fourteen to twentyinches in diameter, divide the I same into shorter len ths, and cut orcrack each section from en to end along a sin le line and while it issubjected to heat in t e flattenin -oven at the entrance to the leer toopen or flatten the same by means of tools.

During this opening rocess the cylinder lies with the cut or crac edline uppermost and the heat in the flattening-oven is such that.

the cylinder'would collapse at each side of the cut or'crack and destroythe glass product, unless skilled attendants, called flatten- 'ers', bytheir toolslift up the glass'along the cut or crack and work the-ed esin opposite directions,. so as to cause t ese edges to gradually comedown to the floor of the oven. This process. requires a hi h-degree ofskill, as the glass is apt to wrink e or bend longitudinally severaltimes if extreme care is not taken to work the edges over evenly and toso smooth or rub what was the inner surface of Specification of LettersPatent. Application filed April19,1906. Serial No- 312,619-

Patented Aug. '7, 1906.

the cylinder carefully and skilfully with.

pieces of Wood. After considerable time and labor these cylindersfinally are pressed down so as to lie fairly flat on theflattening-stone forming the floor of the oven; but this procedure doesnot make the glass entirely flat, as an examination ofordinarywindow-glass will show. The common method just described ofmaking lass'by machinery does not differ very sensi ly from the oldmethod of hand-blowing, the greatest diflerence being in the length ofthe cylinders drawn rather than in their. diameters.

The flattenin of a cylinder of glass by the method 'just escribedproduces a great strain on the glass. The flattening process produces astretchin of the glass in the innerstratum of the cylin er if we mayassume for the present that the cylinder is composed of two concentriccylinders meeting at their adj aoent surfaces and a compression of theouter stratum. This tension or stretching and com ression is present no'matter how slightly t e initial curve or are may be; but it becomes, ofcourse, very great when a half of a cylinder is caused to move away fromits integral other half, so as to eliminate an arc therein. of onehundred and eighty degrees. Not only must the edges of the glass fall orbe drawn down one hundred and eighty degrees, or by a distance equal tothe diameterof the cylinder, but the cylinder must at the same time beunfolded, so that its ed es move laterally cylinder.

It is evident that the material in the outer assumed stratum cannot betransferred to half the circumference of t e 'the stretching innerstratum by the flatten- 'ing process, because any attempt to get theglass sufliciently plastic for that pu ose would produce a collapse anda folding o the glass in spite of the efiorts of the flatteners to I thecontrary. We therefore saw that no imflatten the several se increaseddifficulty in opening the cylinders and bringing them into plane sheetsand of the necessarily-increased size of the furnace, which even with;small cylinders are necessarily too large to be economic andsatisfactorily efficient. We find it practical and economic to drawlarge cylindersfive or six feet in diameter, for example and to divideeach cylinder into segments, preferably four or more, (though therewould stillbe economy over the old'fmetho'ds if a smaller number ofsegments were made) and then preferabl to ents. may before-bein mae'into se ents, as described, be divi ed transverse y into cylindricalsections of the desired lengths.-

To flattenasixteen-inch cylinder in the usual way, each edige musttravel downward sixteen inches an outward about twentyfive inchesto bechanged from a semicircle in cross-section to a flat surface. To flattenone of the four equal segments of a cylinder having a diameter of fivefeet, each edge will travel downwardly less than nine inches andoutwardly less than two and a half inches. The glam sheet developed fromthe said 0 linder will be only about three inches wi r than thatproduced from the said se ment. The tension on the assumed inner andouter strata of the segment is therefore practically negli ible. Thesegment cannot collapse in the attening-oven so that one art thereofwill fall upon another, as would appen with cylinders if attendants werenot employed to v prevent the same, nor would they be likely to wrinkleso much. Such segments as we have described would almost automaticallflatten themselves. Their flattening woul notv require as highly skilledlabor as in the case of entire cylinders, as but slight skill would berequired to press down the edges and rub out the wrinkles, if any.

The larger the cylinders drawn the closer its segments approach a planeand the easier the flatte and the better the product, as the labor dhgskill required and the tension develo d in the assumed strata of theglass would h: reduced. The division of the cylinder in s ents havingshort arcs also accomplishes e same results, because after the divisionof a segment into two se cuts the bending of the glassproceedshal fromeach ed e instead of all from one edge.

y our process we make a decided saving. Comparing the common method.with a sixteen-inch cylinder with ours, wherein, for example, asixty-inch cylinder is divided into four equal segments, we getapproximately four times as much glass in our cylinder at a drawingoperation, which will consume no more time than for the smallercylinder. The roduct of our cylinder will be superior, as it as notundergone such severe strains, and it will be freer from distortion. Itwill also for thisreason be flattened in a shorter time, and

- tive s1ze of the s The cylin ers inder may be divided.

it will not require so high-priced and skilled labor as the integralcylinders require.

After the segments have been flattened they pass into a leer of approvedconstruction.

of drawing the c linders or to their diameter or length or to' t emanner of crackin or dividing the same into segments, or to t erelaen-ts, or'to any method of flattenin and annealing them. We preferto make $11 of one part of the segment collapsing on another; We shouldregard the cutting of a cylinder into two unequal segments as comesegments of such a size that there is no danger, even with unskilledattendants,

, We do not limit ourselves to any manner ing within our invention, asthe formation and treatment of the smaller 5 dividing of t drawn 'nderinto two or t would be employingkethe princi lest reef. The

more cylinders would sti 1 be the practice of our claims, as thecylinders referred to therein are not necessarily the whole cylindermade at a drawing operation, but may be the shorter cylinders into whichthe origmalcyl- Where it is desired to make sheets of standard sizes,such as are made by opening 2. cylinder to form a single sheet, thecircumference of our large sheet may in order to save waste be madesubstantially a multiple of the circumference of the cylinders fromwhich said single standard sizes are made. 1 Thecylinder will be dividedso as to make as many equal segments as the large cylinder is timesgreater than the smaller one. In cases where the said standard sheet isdivided into a number of 'smaller'sheets we may reach the same result bydividing some or al of the segments produced as just described intosmaller segments to correspond with the sizes into which the standardsheet may be divided. Of course, the order in which th large andsmallsegments are made is immaterial.

We claim p 1. Producing a glass cylinder, dividing the whole intoarcshaped segments, and then flattening the segments. 5 2. Producing aglass cylinder, dividing the whole into arc-shaped segments, at leastone having in section an are which, when laid on its convex surface,will have no portion thereof lying over its concave surface, and thenflattening and annealing the segment or segments.

3. Producing a glass cylinder, dividing the whole into arc-shapedsegments, each hav' no portion lying over its concave surface, a h ithen flattening and annealing the s cuts.

4. Producing a lass cylinder w ose circumference is a multiple of thatof a cylinder required to be opened along a le line to cumference ofsaid second 0 linder, flattening said segments, and annea ing the same.

5. Producing a 1ass cylinder Whose circumference is a mu ti le of thatof a cylinder required to be opened along a sin 1e line to form a sheetof redetermined Wi th, dividing said first cy indervinto segments whosearcs are each substantially equal to the circumference of said secondcylinder,- dividing 1 a some or all of said segments into smallersegments, flattening said segments, and annealing the same. I Signed atPittsburg, Pennsylvania, this 17th day of April, 1906.

Witnesses:

F. N. BARBER, O. E. EGGERS.

